Can you tell me the Hei-TORQUE equivalent to my old RZR (or RS) overhead stirrer? There are not 1:1 Hei-TORQUE equivalents for the previous models of overhead stirrers. There are many differences between the ranges. Therefore, you need to consider your requirements (your application etc.), and from that determine the most appropriate Hei-TORQUE model for you. Please see the separate FAQ entry for help with choosing a Hei-TORQUE model. Please feel free to contact us if you require any further guidance.